During interference of waves, the amplitude of the resulting wave can be found at any position using the principle of:
A. Superposition
B. Interference
C. Diffraction
D. None of these

Hint: Interference is the combining up of two waves. We can detect it by two phenomena, destructive and constructive interference. Destructive interference at a point means at that point, the intensity of light wave or simply wave is the minimum. This point is also called minima. Constructive interference at a point means at that point, the intensity of light wave or simply wave is the maximum. This point is also called maxima.

Complete answer:
Here we’ll use the concept of interference of light waves.
But first, let’s understand the standard wave equation.
$Y=asin\left( \omega t+\phi \right)$is called the standard wave equation.
Here ‘Y’ represents the displacement of wave particles at time ‘t’. Coefficient of trigonometric function ‘a’ is called the amplitude of the wave.’$\omega$’ is the angular frequency of the wave, which is the measure of angular displacement. ‘$\phi$’ is the initial phase difference of the wave. It is also called ‘epoch’.
Now, interference is a result of the principle of superposition which states that the combined displacement of any point of two or more waves is the sum of displacements due to individual waves, taken together.

So, the correct answer is “Option A”.

Note:
The main conditions for sustained pattern or sustained interference are that sources must be coherent. Their amplitude must not be varied much. The phase difference between the sources must be zero and both the sources must be monochromatic. In addition to this, they both must be travelling in the same direction and both must be in the same plane.